Expansible bit



J. C. STOKES EXPANSIBLE BIT Nov. 10, 1936.

Filed June 2o, 193s Patented Nov. 10, 1936 UNITED STATES 2.069.352 nxrmvsmm arr John 0. Stokes, Houston, Tex., min... to Feed .Roller Bit CompanyJIouston, 'lex. a corpora- ,tion of Texas Application June 20, weasel-m No. 86,247

18 Claims. (01. 255-) This application relates in general to a rotary underreamer or expansible bit, and has particular reference to a means .for' moving the blades to and from operative position.

It is one object of this invention to provide an underreamer or expansiblebit which will be relatively inexpensive to construct and simple and sure in its operation.

It is an object of this invention-to provide an underreamer, the blades of which will be expanded to operative position, and then contracted to inoperative position, both the expansion and contraction being effected by means of fluid pressure exerted through the drill stem.

It is a further object to provide a means for expanding and contracting'the blades of an underreamer inwhich no mechanical connection is required with the top of the well other than the customary hollow drill stem to which the underreamer is attached.

, It is a further object to provide a means for expanding and contracting the blades of an u derreamer by fluid pressure exerted through the drill stem without preventing the circulation of washing fluid through the drill stem either during or before the operation of the underreamer.

It is a further object to provide a means for expanding and contracting the'blades of anunderreamer in which both' operations are accomplished by downward pressure on the fluid within the drill stem, but in which no retraction of the blades will occur until it is desired by the operator. I

With the foregoing and other objects in view,

. this invention is constituted of the various parts and combinations set forth in the accompanying drawing, and the following description, it

being understood, however, that such disclosure is by way of illustration and example only, and is not to be taken as in any way limiting the spirit or scope of this invention. Such limitation isto be only by the prior art and by the terms of the appended claims.

Referring now more particularly to the drawing in which like numerals indicate corresponding parts throughout:

Fig. 1 is a view partly in elevation and partly in vertical cross section illustrating anunderreamer constructed in accordance with this invention with the blades thereof in expanded or operative position.

Fig. 2 is a view similar to Fig. 1, illustratin the same structure after the blades have been expanded and then retracted.

Fig. 3 is a bottom plan view of the structure as illustrated in Fig. 1.

Referring to Fig. 1 of the drawing, the numeral l indicates a fitting secured to the lower end of the drill stem, and having a reduced 5 externally threaded part 2 at its lower end adapted to threadedly receive the upper end ,3 of the coupling member 4. The lower end'of this coupllng member is similarly reduced and externally threaded at 5 to receive the upper internally 1o threaded end 6 of the barrel or bit head I. Secured within the lower end of the coupling 4 is a ring 8 which may be welded as at 9, or otherwise suitably secured in place, and upon the upper face of which is formed a seat ID for a 15 purpose to be presently set forth.

Within the upper end of the barrel I there is formed a cylinder II; the lower end of which is defined by an annular shoulder l2 extending inwardly from the wall of the barrel 1. Below 20 this shoulder member there is a second space l3 within the barrel which may likewise be of cylindrical or other suitable form. The lower end of the barrel 1 is formed with oppositely disposed downward,projections l4 adapted to 25 embrace the blades of the reamer in the manner to be prese'ntly disclosed. The walls of this barrel! are further provided with passageways l5 extending from a position adjacentthe upper end of the barrel to the lower end of the barrel 30 .andopening at the bottom thereof in positions just ahead of the reamer blades.

Within the barrel 1 and extending past the an-. nular shoulder l2 and the ring 8 is a tubular member l6. Mounted onv this tubular member- I 35 at such aposition as to permit upward and downward sliding movement within the cylinder H is an annular piston l1 secured to the tubular mem- .ber I6 by welding It or the like. provided with piston rings l9 or other suitable 40 This piston is packing.

At its lower end, this tubular member is provided with a plug 20 welded or otherwise secured in place at 2| to close the bore of the tube, and

with a nut 22 threaded on the exterior of the 45 The barrel 1 is formed adjacent its lower end with 66 an internal groove 23 adapted to cooperate with the lugs 29 and lugs 30 on the reamer blades 21 so as to properly position these blades in their extended and retracted positions, respectively.

The lower end of the barrel 1 is furthermore provided with a pair of slots 3| and 32 for the purpose of assembly to make it possible for the upper portions of the blades to be passed upwardly to a position within the barrel as they are illustrated in Figs. 1 and 2. These slots are necessary because the upper ends of these blades are too large to pass into the barrel otherwise.

The upper end of the tubing i6 is closed by means of a plug member 33 welded or otherwise suitably secured in place, and is normally siirrounded by a ring 34 held against longitudinal movement with respect to the tubing by means of a shear pin 35. This ring 34 carries a valve member 36 which may be in the form of a leather washerlor the like adapted when moved downwardly/to seat against the seat In on the ring 8. Above this valve member the ring 34- is threaded to receive the lower end 31 of a second tubular member 38. This member 38 has openings 38 therein so that-the fluid may freely pass into the tubular member, and is closed at its upper end by means of a plug 40 which may be welded into position. The tubular member Iii is provided with lateral openings 4| which are normally closed by .the ring 34 when it is in the position illustrated in Fig. 1. This tubular member is also provided with a second opening 42 just below the annular piston II. It is to be noted that the shoulder i2 is spaced slightly from the wall of the tubing I 6 as illustrated at 43.

The operation of the device just described is as follows:

As the device is lowered into the well, the blades and the tubular member l6 occupy their retracted positions as illustrated in Fig. 2. when the device is being lowered, however, the ring 34 and the tubular member 33 are retained in their upper position by means of the shear pin 35. Upon reaching the lower end of the pipe below which the reaming is to be done, fluid is pumped down through the drill stem and serves to force the piston i1 downwardly and expand the blades 31 until the parts occupy the position illustratedin Fig. 1. During this downward movement of the piston, the fluid therebelow will be allowed to drain out through the space 43. In thisposir tion, itwill beseen that the fluid may still pass down through the drill stem, and that the drilling may take place with washing fluid supplied to the blades 31 through the medium of the passageways ll.

When the drilling is completed, and it is desired to retract the blades and withdraw the reamer, a. weight or go-devil" 44 is dropped into the drill stem and allowed to come in contact with the upper end 43 of the tubular member 33, thus rupturing the shear pin 3! and moving the tubular member 33 to the position illustrated in Fig. 2. In this position, the valve member 33 seatsagainsttheseat llontheringl and prevents further flow of fluid downwardly through the drill stem from impinging upon or influencing thepiston II from the upp r side thereof. At the same time, it moves the tubular member 33 tosuch a position that fluid may enter through the openlugs 33 and .4l 1 into the tubular memberv l3. Thenceitthroughtheopeningfltoa position below thepiston l1 and re-acting against the shoulder It serves to move the piston I! in an upward direction and retract the blades 21.

During the raising of the piston some fluid will of course escape through the space 43, but it is contemplated that a sufl'icient flow of fluid will be obtained to more than overcome this leakage and thus cause upward movement of the piston. After the blades have been retracted, the parts occupy the positions illustrated in Fig. 2 and the reamer may readily be removed from the well.

It will be seen from the foregoing that a means has been set forth for accomplishing all of the objects of this invention. It'is particularly noted that both the expanding and retracting movement of the reamer blades is accomplished by pumping downwardly through the drill stem, and that the retracting movement cannot be caused by pumping downwardly until it is desired by the operator. It is further noted that during the time that the blades areexpanded, washing may continue so that the drilling may properly proceed.

Having described my invention, I claim:

1. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades at the lower end of said head and adapted to he moved into operative position by downward movement of said plunger, a piston on said plunger slidable within said passageway and adapted to be moved downwardly by downward circulation of fluid through said passageway, means releasably secured in position to initially prevent downwardly circulating fluid from acting upon the lower face of said piston, and means for releasing and moving said releasably secured means to permit downwardly circulating fluid to act on the lower face of said piston and to prevent such fluid from acting upon the upper face of said piston.

2. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades at the lower end of said head and adapted to be moved into operative position by downward movement of said plunger, a piston on said plunger slidable within said passageway and adapted to be moved downwardly by downward circulation of fluid through said passageway, means releasably secured to said plunger in position to initially prevent downwardly circulating fluid from acting upon the lower face of said piston, and means for releasing and moving said releasably secured means to permit downwardly circulatingfluid to act on the lower face of said piston and to prevent such fluid from acting upon the upper face of said piston.

3. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter, blades at the lower" end of said head and adapted-to be moved into operative position by downward movement of said plunger, 9. piston on said plunger slidable within said passageway and adapted to be moved downward- 1y by circulation of fluid through said passageway, said plunger being hollow with openings above and below said piston to permit passage of fluid therethrou'gh to act on the lower side of said piston, means releasably secured in position to prevent such passage and movable on release to permit such passage and to prevent fluid from acting upon the upper face of said piston, and means for moving said releasably secured means.

4. In an expansible drill, a drill head having a eway therethrough, a plunger in said passageway, cutter blades at the lower end of said head and adapted to .be moved into operative position by downward movement of said plunger. a piston on said plunger slidable within said passageway below said openings when moved from sageway and adapted to be moved downwardly by downward circulation of fluid through said passageway, said plunger being hollow and having openings above and below said piston to permit passage of fluid therethrough to act on the lower side of said piston, an annular abutment extending inwardly from the wall of said pas-e sageway through said drill head to take the reaction when said fluid is acting on the lower surface of said piston, means releasably secured in position to prevent passage of fluid through said hollowplung'er and movable on release to permit such passage and to prevent fluid from acting on the upper face of said piston, and means for releasing fluid from the space between said piston and said annular abutment when said piston is being moved downwardly.

5. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades at the lower end of said head and adapted to be moved into operative position by downward movement of said plunger,, a piston on said plunger slidable within said passageway and adapted to be moved downwardlyby downward circulation of fluid through said passageway, said plunger being hollow and having openings above and below said piston to permit passage of fluid therethroughto act on the lower side of said piston, a seat in said passageway'above said piston, a collar slidable on said plunger ,and capable of closing the upper openings in said plunger when in one position *thereon and oi seating against said seat to close said passageway below said openings 'whenmoved from such position, and means releasably holding said collar in said flrst named position.

6.. In an expansible drill, a drill head having a I passageway therethrough, a plunger in said passageway, cutter blades at the lower end of said head and adapted to be moved into operative position by downward movement of said plunger, a piston on said plunger slidable within said passageway and adapted to begnoved downwardly by I downwardcirculation of fluid through said passageway, said plunger being hollow and having openings above and below said piston to permit passage of fluid therethrough to act on the lower side of. said piston,- a seat in said passageway above said piston, a collar slidable on said plunger and capable of closing the upper -'openings in said plunger when in one position thereon and of seating against said seat to closesaid'passageway below said openings when moved from such position, alshear pin for holdingsaid collar in saidfirst named position, means on said collar adapted to receive a'weight, and a weight adapted to be 1 dropped against said means to shear said-pin and move the collar against the seat in said passageway.

7. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades at the lower end of said head-and adapted to be moved into operative position by downward movement of said plunger, a piston on said plunger slidable within said passageway; and adapted to be moved downwardly by dqw'nward circulation of fluidthrough said,

' passageway, said plunger being hollow and hav- 1 and of seating against said seat to close said pas- I ing openings above and below said piston to permit passage of fluidtherethrough to act on the lower side of said piston,,a seat in said passageway above said piston, a collar slidable on said plunger and capable'of closing the upper openings in said plunger when in one position thereon such position a shear pin for releasably holding said collar in said flrst named position, a perdropped against said perforated tubular member to shear the pin and'move'the collar against the seat in said passageway.

a. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades at the lower end of said head and adapted to be moved into operative position by downward movement of said plunger, a piston on said plunger slidable within said passageway and adapted to be moved downwardly by downward circulation of fluid through said passageway, said head having its walls formed with other internal passageways leading from within said first passageway at a position above the uppermost position of said piston to the lower end of said head, means releasably secured in position to initially prevent downwardly circulating fluid from acting upon the lower face of said piston, and means for releasing and moving said releasably secured means to permit downwardly circulating fluid to act on the lower face of said upon the upper face of said piston.

9. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades at the lower end of 'said head and adapted to be moved into operative popiston and to prevent such fluid from acting the lower end of said head, means rele'asably secured in position to initially prevent downwardly circulating fluid from acting upon the lower face of said'piston and means for releasing and moving said releasably secured means to permit downwardly circulating fluid to act on the lower face of said piston and to shut off such fluid from the upper face of said pistonand from the entrance to said other passageways.

10. In an expansible drill, a drill head having a passageway therethrough, a plunger, in said passageway, cutter blades atthe lower end of said head and adapted to be moved ,into operative position'by downward movement of said plunger, a piston on said plunger slidable within said passageway and adapted to be moved downwardly by downward circulation of fluid through said passageway, said plunger being hollow and having openings above and below said piston to permit passage of fluid therethrough to act on the lower side of said piston, a seat in said passageway above said piston, said head having its walls formed with other internal passageways leading from said first passageway at a position below said seat and above thenppermost position of said piston and opening atthe lowerend of said .head, a collar slidable on said plunger and capable of closing the. upper openings in said plunger when in oneposition thereon and of seating against saidseat to close said passageway below a operative position by downward movement of said plunger and out of operative position by upward movement thereof, a piston on said plunger slidable within said passageway'and adapted to be moved downwardly by downward circulation of fluid through said passageway. means releasably secured in position to initially prevent downwardly circulating fluid from acting upon the lower face of said piston and means for releasing and moving said releasably secured means to permit downwardly circulating fluid to act on the lower face of said piston and to prevent such fluid from acting upon the upper face of said piston.

12. In an expansible drill, a drill head having a passageway therethrough, a plunger in said passageway, cutter blades carried by the lower end of said plunger and adapted to be moved into operative position by downwardmovement of said plunger and out of operative position by upward movement thereof, a piston on said plunger slidable within said passageway and adapted to be moved downwardly by downward circulation of fluid through said passageway, said plunger being hollow and having openings above and below said piston to permit passage of fluid therethrough to act on 'the lower side of said piston, a seat in said passageway above said piston, a collar slidable on said plunger and capable of closing the upper openings in said plunger when in one position thereon, and of seating against said seat to close said passageway below said openings when moved from such position, a shear pin for releasably holding said collar in said first named position, a perforated tubular member on said collar, said member projecting above said plunger and being closed at its upper end and adapted to receive a weight, and a weight adapted to be dropped against said tubular member to shear said pin and move the collar against the seat in said passageway.

13. In an expansible bit, a drill stem, blades adjacent the lower end of said drill stem, means in and operable by downward pressure within said drill stem for expanding said blades, and means controlling said first means and operable to cause such downward pressure to retract said blades.

14. In an expansible bit, a drill stem, blades adjacent the lower end of said drill stem. means in and operable by downward pressure within said drill stem for expanding said blades. and means controlling said first means and shiftable at the will of the operator to cause such downward pressure to retract said blades.

15. In an expansible bit, a drill stem, blades adjacent the lower end of said drill stem, means in and operable by initial downward pressure within said drill stem for expanding said blades, and means controlling said first means and operable to cause subsequent downward pressure to retract said first means to its initial position.

16. In an expansible bit, a drill stem. blades adjacent the lower end of said drill stem, means in said drill stem carrying said blades and operable by initial downward pressure within said drill stem for expanding said blades, and means controlling said first means and operable to cause subsequent downward pressure to retract said first means to its initial position.

17. In an expansible bit, a drill stem, blades adjacent the lower end of said drill stem, means on said drill stem carrying said blades and operable by initial downward pressure within said drill stem for expanding said blades, and means controlling said first means and operable to cause subsequent downward pressure to retract said blades to their initial position.

18. In an expansible bit, a drill stem, blades adjacent the lower end of said drill stem, means in said drill stem carrying said blades and operable by initial downward pressure within said drill stem for expanding said blades and means controlling said first means and operable to cause subsequent downward pressure to retract said first means to its initial position, said drill stem having passageways for conducting washing fluid to said blades, and said last mentioned means being operable to stop flow of washing fluid through such passageways when operated to cause downward pressure to retract said first means to its initial position.

JOHN C. STOKES. 

